


Unexpected Events

by orphan_account



Category: Ensemble Stars! (Video Game)
Genre: Accidental Bonding, Alpha/Beta/Omega Dynamics, Anal Fingering, Anal Sex, Claiming, Knotting, M/M, Mating Cycles/In Heat
Language: English
Status: Completed
Published: 2017-03-30
Updated: 2017-03-30
Packaged: 2018-10-13 00:31:55
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,321
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10502709
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/orphan_account
Summary: When Tsukasa came of age, it was expected that he would soon present as an alpha, just as his father had, as was most of his family. At the very least, the heir becoming a beta would be accepted as well, but it wasn’t wrong to say everyone was expecting an alpha.Of course, no one was expecting him to present suddenly after practice.





	

Everything was too hot, too rough, and definitely too much to deal with. His body felt like it was on fire, sweat pooling against his clothes and face flushed. His underwear felt just gross, squelching with every twist of his body, and faintly, Tsukasa wondered why he was presenting as an omega of all things.

When Tsukasa came of age, it was expected that he would soon present as an alpha, just as his father had, as was most of his family. At the very least, the heir becoming a beta would be accepted as well, but it wasn’t wrong to say everyone was expecting an alpha. 

Hell, even his unit members were. As Tsukasa was the youngest member, they were coddling him, excited for when he’d present. Already having two alphas in the unit hadn’t been a problem, especially with the other two being betas, and adding a third alpha in wouldn’t be the end of the world. After all, Leo had joked once that Tsukasa was great at taking orders. Alpha or not, he’d listen.

Of course, no one was expecting him to present suddenly after practice. That’s why, after a longer than usual run-through of their next live, there hadn’t been any complaint of leaving Tsukasa with Izumi to take him home. They’d done it plenty of times, and with the probability that Tsukasa would present as an Alpha, it wasn’t the worst idea.

Now, though, as Tsukasa whined and shivered, back against the wall of the classroom, he was having second thoughts about if it was such a good idea. Izumi had left to use the restroom, and only a few moments after he left, Tsukasa was hit by it. He wasn’t stupid; he’d received education on the workings of alphas, betas, and omegas since he was a kid. 

There was something different in reading about an omega heat than experiencing it. His legs pressed together tightly, and he fought to try to regain his footing, leaning against the wall and panting. He felt so empty it hurt. Pulling one foot in front of the other, he used the wall to guide himself towards the door, waiting to see when Izumi would get back.

He hears his footsteps before he sees him, and Tsukasa realizes in a haze that Izumi was running back, which seemed silly to him. When he stopped at the door, eyes wide and gaze focused on Tsukasa, the omega had a moment to appreciate the other’s scent, something he hadn’t noticed before now. It was nice, comforting, and he followed it until he was interrupted by the alpha.

“Kasa-kun.”

Tsukasa looked at him immediately, freezing at the tone and feeling a shiver run down his back, slick coating his underwear more. He could tell it was an alpha tone, having grown up hearing such tone when he’d misbehave, but that was nothing compared to how much more his body craved Izumi. 

“S-sena-senpai…” He whimpered, more slick sliding down the legs of his uniform pants. “I- I don’t- need you…” His words were getting mixed up, worse and worse when he inhaled the alpha’s scent.

“This is your first heat… Of course it is, how irritating.” Izumi moved into the room, further from Tsukasa, before he got to his bag. Of course he had some level of self-restraint, especially when his cute unit member was experiencing a heat for the first time. It couldn’t have been easy, and he could see the desperate look in Tsukasa’s eyes.

“Sena-senpai, I feel empty,” Tsukasa whined, hand going to the front of his slacks without thought. He rubbed at the hard-on already pressing against the fabric, biting his lip. The friction felt okay, but it wasn’t what he wanted at all. He needed something inside him, and when his line of vision dropped to the rising bump in Izumi’s pants, he knew he had to convince Izumi to stay.

“I need to call someone to get you...You don’t have suppressants, either? Ugh…” The alpha was clearly affected by Tsukasa’s scent. It was sweet, enticing, and it took all of Izumi’s willpower not to tackle Tsukasa to the floor and knot him when he first smelled it from the bathroom.

“Sena-senpai…~” Tsukasa had come closer when he was distracted with rummaging through his bag for his phone, and Izumi shivered when he felt the omega slide to his front, hands gripping the bag and tugging it down, away from Izumi. It was distracting the alpha when he should have only been thinking about what Tsukasa needed.

“Kasa-kun,” Izumi began, only to have the first year shake his head.

“Sena-senpai, I’m so empty, it hurts. I need you. Alpha, please!” Tsukasa shook as he pleaded, and Izumi felt the need to help him, to fuck Tsukasa through his heat and stuff him until he can barely walk.

“The futon,” Izumi said. Tsukasa’s hands moved to start undoing buttons as he made his way to the futon in the corner of the room. “Get undressed,” Izumi added, as if Tsukasa needed more instruction.

Tsukasa, upon reaching the futon, only had to wriggle out of his boxers. When he did, the effect was instantaneous. His scent flooded the room, and Izumi couldn't shut the door fast enough. 

“Such a good omega,” Izumi cooed as he crossed the room to him. Tsukasa nodded, embarrassment and need flushing his face and body. Izumi drank in every detail, from the ultimate lack of hair on Tsukasa’s front to the small, cute dick that leaked with precum. He growled softly, causing Tsukasa to shiver and turn into his knees, looking over his shoulder at his senpai. 

“Sena-senpai- alpha, please~! I feel so empty, I- I need your knot,” Tsukasa whined, so gone in his heat to even register what he was babbling. Izumi wasn't.

It’s within moments that Izumi’s hands were on Tsukasa’s hips, drawing them back, then persistently pushing at his shoulder blades until Tsukasa’s face was pressed against the futon and his ass raised, presenting his hole to Izumi. 

The alpha could only take a moment to appreciate the sight before the omega whined, shaking, and more slick dripped onto his thighs. He leaned in, eyes closing briefly as he inhaled, and Tsukasa’s scent made him harder than he remembered being in a while. He held onto Tsukasa’s ass with one hand, using him for balance while the other unbuttoned his slacks and shoved them down.

“So pretty, Kasa-kun…” Izumi mumbled, pulling Tsukasa’s cheeks apart to show his hole more clearly. Tsukasa wriggled back into Izumi’s hand, biting his lip and moving his arms to cover his face and support him just a bit more, so his alpha could do what he wanted to him. He let out a loud moan when Izumi’s thumb finally swiped over his hole and another when one, then two fingers slipped in with no resistance. “So nice and ready, just for me,” Izumi said, biting back a groan when Tsukasa pushed himself back against his fingers. 

“Alpha, please, it hurts,” Tsukasa whined, and Izumi couldn’t help but want to hear that voice a bit more before he actually gave him what he wanted.

“What hurts?” Izumi asked. It was a bit cruel, teasing his junior like this, especially during his first heat, but Izumi was fond of teasing his juniors, and when Tsukasa was so responsive for once, the opportunity couldn’t pass itself up.

“M-my…” Tsukasa’s voice trailed off and Izumi frowned, curling his fingers inside the omega until he moaned again, head tilting up. “My hole...p-please, I need you,” he panted, any other words melting into another moan when Izumi easily added a third finger. It was getting harder to resist the urge to mount him now, and with a groan of self-restraint Izumi pulled his fingers from Tsukasa. He moved to lean over Tsukasa’s back, hips pressing against the younger’s, and it was clear that Izumi was much more affected by the scent of the heat than he was letting on. 

His dick pressed against Tsukasa’s ass, and the first year almost let out a sob at how close it was to filling him up. “What was it that you wanted?” Izumi asks, hands moving to grip the younger boy’s hips as he lowered his head to his ear, speaking low.

“Y-your alpha cock!” Tsukasa cried, tears of frustration gathering in his eyes. It’s almost too much now, bordering on painful, and he doesn’t understand why Izumi’s taking so long to enter him. “Alpha I need you, it hurts, I n-need you to fill me and knot me a-and-” His voice stutters off as tears slip from his eyes. Izumi notices them, and his teasing attitude calms in favor of turning to kiss Tsukasa’s cheek, pulling his hips back to line himself up with Tsukasa’s hole.

“Don’t worry, I will, Kasa-kun,” he murmured as he slowly pressed forward. Tsukasa’s hole easily opened to him, and the copious amounts of slick he’d been leaking made the entrance even easier on the omega. As Izumi inched into him, a deep rumbling in his chest, Tsukasa moans, voice breaking into incoherent whines and babbling. Tears flowed easier, the stimulation of it all catching up to Tsukasa, even if it wasn’t enough to actually get him to cum. 

“More,” the omega whined as Izumi paused, pressed deeply into Tsukasa. Izumi raised an eyebrow at the demanding nature of Tsukasa, noticing how his hips twitched and moved as if he didn’t even notice, body wanting more and it barely transitioning into words. “Please, alpha, please, more!”

“Needy brat…” Izumi mumbled. There was hardly any venom to his words, and he punctuated them with a sharp thrust, drawing out halfway and pushing back in fully. He began a steady pace, hands gripping Tsukasa’s lips.

The smell of sex and pheromones quickly saturated the room, and the sound of skin slapping against skin grew louder. Izumi growled lowly, nuzzling into the crook of Tsukasa’s neck and shoulder. 

“I need more~” Tsukasa whined, arching against Izumi’s chest. He tilted his head and bared his neck instinctively, moaning and trying to get more of Izumi inside him. “I’m so close, please alpha, I- I need-”

“What?” Izumi growled as he licked up the side of Tsukasa’s neck. His knot was beginning to swell, bumping against Tsukasa’s hole and causing the omega to let out a drawn-out moan. “What do you need, Kasa-kun?”

“Your kno- haah~ Sena-senpai’s knot,” Tsukasa panted. Izumi nodded, nuzzling against Tsukasa’s neck again. That sounded like a good idea. 

“I’ll knot you,” he promised. He nibbled at Tsukasa’s neck as he put more power into his thrusts, knot swelling and bumping against Tsukasa’s hole harder with every thrust. “Get ready.”

Tsukasa nodded, moving his arms to brace himself properly. That all went to waste, however, when he felt Izumi’s knot pressing into him, stretching him wide and leaving him gasping for breath. It was so much, almost too much, and he froze as Izumi continued to press into him. He could barely remember how to breathe, let alone how to form words, so he resorted to a low whine that grows in volume until Izumi’s knot pressed into him at it’s widest part, then slipped the rest of the way inside him.

Tsukasa sobbed, still so close but missing something. “Alpha, you’re so- haa-!” Izumi tugged him closer sharply, hips pressing roughly against Tsukasa and teeth grazing the omega’s neck.

“Mine,” Izumi growled, pounding his hips harder against Tsukasa. The first year nodded, breath hiccuping when he felt Izumi’s teeth scrape against him harder. “My omega.”

“I’m yours,” Tsukasa cried, baring his neck more for Izumi. “Please, alpha, I’m close- I’m yours,” he panted, head fuzzy from the thickness of the air. 

Tsukasa thought Izumi might have mumbled ‘mine’ again, but it was lost in a burst of white-hot pleasure when Izumi thrust into him just right, combined with the sudden, impulsive bite against his neck. Tsukasa came, his small cock painting white over the futon. In his haze, he could feel Izumi humping against him, tongue laving over the bite mark on Tsukasa’s neck, and then a deep, possessive growl. He felt Izumi’s cum pumping into him, filling him almost obscenely as he whined from the slight over-stimulation of Izumi’s still-moving hips.

He wasn’t sure how long they laid like that, but he was conscious to hear the distinct “ _fuck_ ” when Izumi fully realized what happened. His knot deflating enough, he carefully pulled out of Tsukasa. Already, the omega could feel the prickles of sweat beading at his skin, the familiar heat pooling in his stomach. His cock twitched again, a purr rumbling in his chest when he felt Izumi’s cum slowly dripping out of his hole.

“Sena-senpai…” Tsukasa murmured, grabbing Izumi’s attention immediately. “D- did you…?” Izumi’s face looked flushed, embarrassed and obviously mortified at the implication of that bite.

“It was the heat of the moment. It’s your fault, letting your scent all over the place while I was in the bathroom,” Izumi said instead, moving to stand and find something to clean the both of them off. Tsukasa whined, reaching out and grabbing onto Izumi’s arm. He rolled onto his back to pull the alpha above him, gaze already becoming hazy with the effects of his heat.

“Sena-senpai, I still feel empty…” He said softly, hands pulling at the shirt Izumi was still wearing. “You’re my alpha. Take care of me.” It almost made Izumi laugh, with how bossy the omega was being, but he obliged, leaning down to press a deep kiss against his lips before moving to press another over the mark that had claimed the omega as ‘his’. 

Later, he decided as he wrapped his hand around Tsukasa’s hardening cock and smirked at the whimpering, needy sounds coming from his omega, he could deal with having claimed the boy for his own.

**Author's Note:**

> Written for a prompt on the kinkmeme. This was my first time writing ABO in any fandom so I hope that it went along well! Thank you for reading this!


End file.
